In a home network appliance (single or plural) that receives a plurality of services including a broadcast service, an IPTV (Internet Protocol Television) service, a package distribution service of a DVD (DVD: Digital Versatile Disc), a BD (Blu-ray Disc), an HDDVD (High Definition DVD), and the like, contents or metadata of the contents that are distributed across those plurality of media and networks are distributed using protocols that depend on the media. Moreover, when the contents or metadata thereof distributed by the protocols that depend on the media and services are updated, if the protocols each support an update function, update processing is carried out by a method that depends on that protocol. Therefore, in a case where the contents or the metadata are updated on a provider side, if an application capable of detecting those update events is activated on a client side, the update detection and the update processing can be carried out.
Patent Document 1 discloses a technique in which a user terminal periodically polls, with respect to a content distribution server providing contents or metadata of the contents, whether the metadata is updated, and when the metadata is updated, requests the updated metadata of the content distribution server and acquires it.    Patent Document 1: Japanese Patent Application Laid-open No. 2006-053633 (paragraph 0083)